Entry doors customarily include one or more door locks, such as, a doorknob lock or deadbolt. Each lock extends through an opening in the door and typically includes a stem with a mechanism including a key slot at the outer end of the stem. When a key is inserted into the slot and rotated, it will cause the stem to rotate about its longitudinal axis to release a door latch from a normally locked position extending into the door jamb.
Various means have been devised in the past to illuminate a doorway, such as, light fixtures placed over the door. Although these are effective to some extent in illuminating the door lock itself so as to avoid hunting for the slot or properly inserting the key into the slot, a more efficient means of lighting is desirable. It has also been proposed in the past to incorporate a lighting device directly into the doorknob or locking device so as to be situated in close proximity to the key slot and to better illuminate the slot to facilitate locking or unlocking of the door. Among other drawbacks in illuminating devices of the type that have been utilized in the past is that they have to be left on all the time and use up excess energy, often require substantial redesign and increase in size of the lock itself, or require a separate switch or electrical connection to activate the light source each time.